public static string GetPathForCachedFile(string fileUrl)
{
int cacheEntryInfoBufferSize = 0;
IntPtr cacheEntryInfoBuffer = IntPtr.Zero;
int lastError; Boolean result;
try
{
// call to see how big the buffer needs to be
result = GetUrlCacheEntryInfo(fileUrl, IntPtr.Zero, ref cacheEntryInfoBufferSize);
lastError = Marshal.GetLastWin32Error();
if (result == false)
{
if (lastError == ERROR_FILE_NOT_FOUND)
{
return(null);
}
}
// allocate the necessary amount of memory
cacheEntryInfoBuffer = Marshal.AllocHGlobal(cacheEntryInfoBufferSize);
// make call again with properly sized buffer
result = GetUrlCacheEntryInfo(fileUrl, cacheEntryInfoBuffer, ref cacheEntryInfoBufferSize);
lastError = Marshal.GetLastWin32Error();
if (result == true)
{
Object strObj = Marshal.PtrToStructure(cacheEntryInfoBuffer, typeof(LPINTERNET_CACHE_ENTRY_INFO));
LPINTERNET_CACHE_ENTRY_INFO internetCacheEntry = (LPINTERNET_CACHE_ENTRY_INFO)strObj;
//INTERNET_CACHE_ENTRY_INFO internetCacheEntry = (INTERNET_CACHE_ENTRY_INFO)strObj;
String localFileName = Marshal.PtrToStringAuto(internetCacheEntry.lpszLocalFileName); return(localFileName);
}
else
{
return(null);// file not found
}
}
finally
{
if (!cacheEntryInfoBuffer.Equals(IntPtr.Zero))
{
Marshal.FreeHGlobal(cacheEntryInfoBuffer);
}
}
}
// 返回 指定URL文件的缓存在本地文件系统中的路径
public static string GetPathForCachedFile(string fileUrl)
{
int cacheEntryInfoBufferSize = 0;
IntPtr cacheEntryInfoBuffer = IntPtr.Zero;
int lastError; Boolean result;
try
{
result = GetUrlCacheEntryInfo(fileUrl, IntPtr.Zero, ref cacheEntryInfoBufferSize);
lastError = Marshal.GetLastWin32Error();
if (result == false)
{
if (lastError == ERROR_FILE_NOT_FOUND)
{
return(null);
}
}
cacheEntryInfoBuffer = Marshal.AllocHGlobal(cacheEntryInfoBufferSize);
result = GetUrlCacheEntryInfo(fileUrl, cacheEntryInfoBuffer, ref cacheEntryInfoBufferSize);
lastError = Marshal.GetLastWin32Error();
if (result == true)
{
Object strObj = Marshal.PtrToStructure(cacheEntryInfoBuffer, typeof(LPINTERNET_CACHE_ENTRY_INFO));
LPINTERNET_CACHE_ENTRY_INFO internetCacheEntry = (LPINTERNET_CACHE_ENTRY_INFO)strObj;
String localFileName = Marshal.PtrToStringAuto(internetCacheEntry.lpszLocalFileName); return(localFileName);
}
else
{
return(null); // fileName not found
}
}
finally
{
if (!cacheEntryInfoBuffer.Equals(IntPtr.Zero))
{
Marshal.FreeHGlobal(cacheEntryInfoBuffer);
}
}
}
